The enigma of electric currents in the seabed is solved. Scientists from Aarhus University have sensationally discovered seabed bacteria that function with a living neuro-electrical network.

We call such features nerves and nervous systems (aka brains) in higher life forms. Each of the centimetre-long ‘cable bacteria’ contains a bundle of insulated wires, nerves,  leading an electric signal from one end to the other. 

Features almost exactly like higher life nerves in bacterial mats explain electric currents in the seabed

Electricity and seawater are usually a bad mix. And it was thus a very big surprise when scientists from Aarhus University a few years ago discovered electric currents between biological processes in the seabed. Since then they have been searching for an explanation and together with partners from the University of Southern California, USA, they now present sensational results in Nature.

“Our experiments showed that the electric connections in the seabed must be solid structures built by bacteria,” says PhD student Christian Pfeffer, Aarhus University.

He could interrupt the electric currents by pulling a thin wire horizontally through the seafloor. Just as when an excavator cuts our electric cables or doctor slices through nerves in an operation.

In microscopes, scientists found a hitherto unknown type of long, multi-cellular bacteria that was always present when scientists measured the electric currents.

The incredible idea that these bacteria should be revealing nerve like structures really fell into place when, inside the bacteria. They saw nerve-like strings enclosed by a membrane.  Report the author Nils Risgaard-Petersen, Aarhus University.

Kilometers of living cables… living nerves, an enormous nervous system.

The bacterium is one hundred times thinner than a hair and the whole bacterium functions as an nervous system with a number of nerves within it. Quite similar to the nerves we know from our daily lives.

“Such unique insulated biological wires seem simple but with incredible complexity at nanoscale,” says PhD student Jie Song, Aarhus University, who used nanotools to map the electrical properties of the cable bacteria.

In an undisturbed seabed more than tens of thousands kilometers cable bacteria live under a single square meter seabed. The ability to conduct an electric current gives cable bacteria such large benefits that it conquers much of the energy from decomposition processes in the seabed.

Unlike all other known forms of life, these bacteria maintain an efficient combustion down in the oxygen-free part of the seabed. It only requires that one end of the individual reaches the oxygen which the seawater provides to the top millimeters of the seabed. The combustion is a transfer of the electrons of the food to oxygen which the bacterial inner wires manage over centimeter-long distances. However, small disturbances can lead to fatal “cable breakage” in the fragile bacteria.

Biological innovation

“On the one hand, it is still very unreal and fantastic. On the other hand, it is also very tangible,” says Professor at Aarhus University, Lars Peter Nielsen, who is in charge of exploring the natural electrical currents.

Along with a number of international cooperation partners, several scientists at Aarhus University already address the new and exciting questions that arise. Right from the understanding of bioelectronics at the molecular level to the role of cable bacteria in the history of Earth.

The future will tell whether this wondrous result of the biological evolution can also be used in new types of electronics.

Or perhaps the more obvious concept is that life of all forms finds use in being able to use bio-electrical management makes life more capable. Wonderful inventions of evolution and nature are very rarely unique to just one sort of life. All the really great inventions are widely distributed throughout all life. That’s why we humans and even those seabed bacteria share a large number of genes…

I wonder if seabed bacteria have bluetooth?  My bet is they do… see how the inventor of such networking fits into this, she’s not your ordinary Hollywood beauty queen….read more here. Plankton have neural nets too!

In Nature:

“Filamentous bacteria transport electrons over centimetre distances” by Christian Pfeffer, Steffen Larsen, Jie Song, Mingdong Dong, Flemming Besenbacher, Rikke Louise Meyer, Kasper Urup Kjeldsen, Lars Schreiber, Yuri A. Gorby, Mohamed Y. El-Naggar, Kar Man Leung, Andreas Schramm, Nils Risgaard-Petersen & Lars Peter Nielsen. DOI:10.1038/nature11586. Link to the article in Nature

ed note: The almost identical lower life form electrically conducting nerve like net is reported widely amongst trees that grow in groves where their roots are grafted together. Read about the thinking trees here.